Broadcast systems, such as mobile telephone communication systems, often experience problems in “multipath environments.” A multipath environment can occur when a broadcasted signal reflects or scatters off various objects such as buildings, water towers, airplanes, or cars. A receiver (such as a cell phone) may receive these reflected signals along with the direct or line-of-sight signal. The reflected signals and direct signal may each arrive at slightly different times at the receiver, causing confusion and errors.
This multipath problem is particularly significant in data communications where the difference in arrival times is long compared to the modulation rate of the signals. The multipath problem is also significant in mobile communications where the cell phone may receive many different or changing reflected signals as it moves